The invention relates to a control circuit arrangement for solenoid valves comprising a timer adapted to supply the solenoid valve with a higher attraction current during a preset time interval as from the beginning of a solenoid valve operating signal so that after the end of the time interval a lower holding current flows until the end of the operating signal.
In order to prevent overheating of solenoid valves and in order to reduce the current requirement it is a known practice initially to supply solenoid valves with a high attraction current which ensures reliable attraction by the solenoid valve and then to switch over to a very much lower holding current, which ensures that the solenoid valve is maintained in the attracted condition. As an example, a given type of solenoid valve may be supplied with an attraction current of 220 mA during a time of 20 msecs and after this the current is then reduced to 17 mA. Circuits for performing such a function are more particularly to be found with an analog (as opposed to digital) function. In order to attain reproducible operation it is necessary for the operating voltages to be very precisely observed. Furthermore, substantial operating powers are required. There are also system limits as regards the possibility of integration and of arrangement in very small spaces, more especially as regards the capacitors required.